Night Vision Illumination Control for Halation and Black Crush
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Night vision imaging apparatuses face challenges in maintaining consistent illumination across varying distances, leading to issues like halation and black crush due to the dynamic range limitations, especially when imaging scenes with objects at different distances, which results in reduced frame rates and increased device bulkiness.
Innovation Solution
A night vision imaging apparatus with a light projecting section that uses near infrared rays and a light amount controller to divide the image into sub-areas, determining and adjusting the illumination light intensity for each sub-area, allowing for proper exposure and reducing brightness differences across the image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uniform illumination light is used across the entire imaging area, then the device structure remains simple, but objects at different distances exhibit large brightness differences causing halation and black crush
Solution Approach 1:
The imaging area is divided into multiple regions (near field, middle field, far field) with different illumination requirements. The controller separately controls illumination intensity for each region, applying stronger illumination to distant areas and weaker illumination to near areas, thereby achieving uniform brightness across the entire image without requiring complex hardware modifications.
Solution Approach 2:
Different illumination intensities are applied to different spatial regions of the imaging area. The controller adjusts the light output of individual LEDs or LED groups based on their position and the distance to the imaging plane, creating locally optimized illumination conditions for near objects, middle-distance objects, and far objects simultaneously.
2Illumination intensity
If multiple images with different shutter speeds are used to overcome narrow dynamic range, then exposure quality improves, but frame rate decreases to 5-15 frames/second
Solution Approach 1:
The system pre-calculates and pre-sets the illumination intensity for each region before imaging occurs. By dividing the imaging area into near, middle, and far field regions and assigning appropriate illumination levels in advance, the system achieves proper exposure for all distances simultaneously in a single frame, eliminating the need for multiple sequential exposures and maintaining high frame rates.
3Illumination intensity
If the light-emitting area is limited to one area within the angle of view, then proper exposure is achieved in each area, but the device becomes bulky due to increased frame rate requirements
Solution Approach 1:
The system uses dynamic control of LED illumination intensity rather than physical movement or multiple fixed light sources. The controller rapidly adjusts the output of each LED or LED group based on real-time imaging requirements, enabling flexible illumination of different regions without mechanical complexity or increased device size.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables high-quality imaging in low luminance conditions by adjusting illumination levels dynamically, reducing halation and black crush, and maintaining a higher frame rate without increasing device bulkiness.
Implementation Method 1
a light source element emitting a near infrared ray
Data Source
AI summary
A night vision imaging apparatus includes a light projecting section, a light amount controller, an imaging section, and a recording section. The light projecting section casts a near infrared ray as illumination light on an illumination area. The light amount controller controls an amount of the illumination light on each one of sub-areas forming the illumination area. The imaging section images the illumination area, and generates image data. The recording section records the image data generated by the imaging section. The light amount controller divides an image shown in the image data into a plurality of divided portions, and determines a light intensity of each one of the plurality of divided portion, and then controls an amount of the illumination light to be casted on a sub-area corresponding to each one of the plurality of divided portions among the sub-areas of the illumination area based on the determined light intensity.